technetium-tc-99m-exametazime and Myocardial-Infarction

The injection of stem cells in the context of acute myocardial infarction (AMI) has been tested almost exclusively by anterograde intra-arterial coronary (IAC) delivery. The retrograde intravenous coronary (IVC) delivery may be an additional route.. To compare the cell distribution and retention pattern in the anterograde and retrograde routes. To investigate the role of microvascular obstruction by magnetic resonance imaging in cell retention by cardiac tissue after the injection of bone marrow mononuclear cells (BMMC) in AMI.. This was a prospective, open label, randomized study. Patients with AMI who presented: (1) successful chemical or mechanical reperfusion within 24 hours of symptom onset and (2) infarction involving more than 10% of the left ventricle (LV) at the myocardial scintigraphy were included in the study. One hundred million BMMC were injected into the infarction-related artery through IAC route, or vein through the IVC route. One percent of the injected cells were labeled with 99mTc-hexamethyl-propylene-amine-oxime (99mTc-HMPAO). Cell distribution was evaluated at 4 and 24 hours after the myocardial scintigraphy injection. Cardiac magnetic resonance imaging was performed before cell injection.. Thirty patients were randomized into three groups. There were no serious adverse events related to the procedure. The early and late retention of labeled cells was higher in the IAC group than in IVC group, regardless of the presence of microcirculation obstruction.. The injection using the retrograde approach was feasible and safe. Cell retention by cardiac tissue was higher using the anterograde approach. More studies are needed to confirm these findings.

Topics: Bone Marrow Transplantation; Coronary Vessels; Female; Humans; Injections, Intra-Arterial; Male; Microcirculation; Middle Aged; Myocardial Infarction; Prospective Studies; Radionuclide Imaging; Radiopharmaceuticals; Statistics, Nonparametric; Stem Cell Transplantation; Technetium Tc 99m Exametazime

The objective of this study was to investigate safety and feasibility of autologous bone marrow mononuclear cells (BMMNC) transplantation in ST elevation myocardial infarction (STEMI), comparing anterograde intracoronary artery (ICA) delivery with retrograde intracoronary vein (ICV) approach. An open labeled, randomized controlled trial of 30 patients admitted with STEMI was used. Patients were enrolled if they 1) were successfully reperfused within 24 h from symptoms onset and 2) had infarct size larger than 10% of the left ventricle (LV). One hundred million BMMNC were injected in the infarct-related artery (intra-arterial group) or vein (intravenous group), 1% of which was labeled with Tc(99m)-hexamethylpropylenamineoxime. Cell distribution was evaluated 4 and 24 h after injection. Baseline MRI was performed in order to evaluate microbstruction pattern. Baseline radionuclide ventriculography was performed before cell transfer and after 3 and 6 months. All the treated patients were submitted to repeat coronary angiography after 3 months. Thirty patients (57 +/- 11 years, 70% males) were randomly assigned to ICA (n = 14), ICV (n = 10), or control (n = 6) groups. No serious adverse events related to the procedure were observed. Early and late retention of radiolabeled cells was higher in the ICA than in the ICV group, independently of microcirculation obstruction. An increase of EF was observed in the ICA group (p = 0.02) compared to baseline. Injection procedures through anterograde and retrograde approaches seem to be feasible and safe. BMMNC retention by damaged heart tissue was apparently higher when the anterograde approach was used. Further studies are required to confirm these initial data.

Topics: Acute Disease; Adolescent; Adult; Aged; Aged, 80 and over; Bone Marrow Transplantation; Demography; Female; Humans; Injections; Leukocytes, Mononuclear; Male; Middle Aged; Myocardial Infarction; Nitrates; Radionuclide Ventriculography; Technetium Tc 99m Exametazime; Technetium Tc 99m Sestamibi; Transplantation, Autologous

The precise localization of bone marrow stem cells (SCs) into the necrotic tissue after intracoronary infusion (ICI) may be important for the therapeutic outcome. This study aims to examine the correlation between Tl-201 and Tc-99m-hexa-methyl-propylene-amine-oxime (HMPAO) images.. Thirteen patients, aged 36-62 years, with an old, nonviable, anterior myocardial infarction (MI) and reduced myocardial contractility (LVEF <40%), underwent ICI of selected CD133(+) and CD133(neg)CD34(+) SCs. One hour after the ICI, SPECT imaging with Tc-99m-HMPAO was performed in all patients and the acquired images were compared with the images obtained during the initial imaging for demonstration of viability (myocardial perfusion imaging with pharmacologic stress and Tl-201). Furthermore, two fused bull's eye images of Tc-99m-HMPAO and Tl-201 rest reinjection were created in six patients and regions of interest were set on Tl-201 and Tc-99m-HMPAO bull's eye images.. The comparison of the two sets of images revealed an intense accumulation of the SCs in the infarcted area with absence of viability as assessed by Tl-201 reinjection images. In the subset of patients in whom fused bull's eye images were produced, the comparison demonstrated that the percentage of the infarcted area with SCs' adherence was 83.2 ± 17%.. Tl-201 images are complementary with the respective Tc-99m-HMPAO ones, revealing a precise localization of SCs in the infarcted area. Tc-99m-HMPAO labeling of SCs is a reliable method for cell monitoring after ICI in nonviable myocardium after an anterior MI.

Topics: Adult; Bone Marrow Cells; Cell Adhesion; Female; Humans; Male; Middle Aged; Myocardial Infarction; Myocardium; Necrosis; Radionuclide Imaging; Retrospective Studies; Stem Cells; Technetium Tc 99m Exametazime; Thallium Radioisotopes; Time Factors

To investigate the kinetics of myocardial engraftment of bone marrow-derived mononuclear cells (BMNCs) after intracoronary injection using 99mTc-d,l-hexamethylpropylene amine oxime (99mTc-HMPAO) nuclear imaging in patients with acute and chronic anterior myocardial infarction.. Nuclear imaging-derived tracking of BMNCs at 2 and 20 h after injection in the left anterior descending (LAD) coronary artery.. Academical cardiocentre.. Five patients with acute (mean (SD) age 58 (11) years; ejection fraction range 33-45%) and five patients with chronic (mean (SD) age 50 (6) years; ejection fraction range 28-34%) anterior myocardial infarction.. A total of 24.2 x 10(8)-57.0 x 10(8) BMNCs (20% labelled with 700-1000 MBq 99mTc-HMPAO) were injected in the LAD coronary artery.. At 2 h after BMNC injection, myocardial activity was observed in all patients with acute (range 1.31-5.10%) and in all but one patient with chronic infarction (range 1.10-3.0%). At 20 h, myocardial engraftment was noted only in three patients with acute myocardial infarction, whereas no myocardial activity was noted in any patient with chronic infarction.. Engraftment of BMNCs shows dynamic changes within the first 20 h after intracoronary injection. Persistent myocardial engraftment was noted only in a subset of patients with acute myocardial infarction.

Topics: Acute Disease; Aged; Bone Marrow Cells; Bone Marrow Transplantation; Chronic Disease; Coronary Vessels; Graft Survival; Humans; Injections, Intralesional; Male; Middle Aged; Myocardial Infarction; Pharmacokinetics; Radionuclide Imaging; Radiopharmaceuticals; Stroke Volume; Technetium Tc 99m Exametazime

Adult endothelial progenitor cells (EPCs) reduce myocardial infarct size and improve postischemic myocardial function. We have recently shown that clonal embryonic EPCs (eEPCs), derived from 7.5-day-old mice, home specifically to hypoxic areas in tumor metastasis mouse models but spare normal organs and do not form carcinomas. Here, we assessed the potential of eEPCs to limit organ dysfunction after ischemia and reperfusion in a preclinical pig model.. Pigs were subjected to ischemia (60-minute left anterior descending [LAD] artery occlusion) and reperfusion (7 days). At the end of ischemia, we applied medium with or without 5 x 10(6) eEPCs by either pressure-regulated retroinfusion or intravenous transfusion. One hour after reperfusion, 99Tc-labeled eEPCs engrafted to a 6-fold higher extent in the ischemic myocardium after retroinfusion than after intravenous application. Regional myocardial function (subendocardial segment shortening [SES] at 150/min, given in percent of nonischemic circumflex region) and infarct size (TTC viability and Methylene-blue exclusion) were determined 24 hours and 7 days later. Compared with medium-treated animals, retroinfusion of eEPCs decreased infarct size (35+/-4% versus 51+/-6%) and improved regional myocardial reserve of the apical LAD region (SES 31+/-4% versus 6+/-8%), whereas intravenous application displayed a less pronounced effect (infarct size 44+/-4%; SES 12+/-3%). Retroinfusion of an equal amount of neonatal coronary endothelial cells (rat) did not affect infarct size (49+/-5%) nor regional myocardial reserve (16+/-7%). The eEPC-dependent effect was detected at 24 hours of reperfusion (infarct size 34+/-7% versus 58+/-6%) and was sensitive to Wortmannin coapplication (50+/-5%).. Our findings show that eEPCs reduce ischemia-reperfusion injury in a preclinical pig model. The rapid effect (as early as 24 hours) indicates a role for enzyme-mediated cardioprotection, which involves, at least in part, the phosphatidylinositol 3-kinase/AKT pathway.

Topics: Androstadienes; Animals; Apoptosis; Cell Hypoxia; Cells, Cultured; Coronary Vessels; Fetal Tissue Transplantation; Heart Ventricles; Hematopoietic Stem Cell Transplantation; Infusions, Intravenous; Jugular Veins; Mice; Myocardial Infarction; Myocardial Ischemia; Myocardial Reperfusion Injury; Myocytes, Cardiac; Peroxidase; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Pressure; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Radiopharmaceuticals; Rats; Sus scrofa; Technetium Tc 99m Exametazime; Transplantation, Heterologous; Wortmannin

Platelets (Plt) accumulate in reperfused myocardium but their effect on myocardial necrosis has not been established. We tested the hypothesis that the effect of Plt depends on their activation status. Pig Plt were obtained before 48 min of coronary occlusion (pre-CO-Plt), 10 min after reperfusion (R-Plt), or after a 60-min sham operation (sham-Plt). Plt were infused into isolated rat hearts (n = 124) and subsequently submitted to 60 min of ischemia and 60 min of reperfusion. P-selectin expression was higher (P = 0.02) in R-Plt than in pre-CO-Plt or sham-Plt. Lactate dehydrogenase (LDH) release during reperfusion was similar in hearts receiving pre-CO-Plt, sham-Plt, or no Plt, but R-Plt increased LDH release by 60% (P = 0.004). Activation of pre-CO-Plt with thrombin increased P-selectin expression and LDH release (P < 0.001), and these results were unaffected by tirofiban. There was a close correlation between P-selectin expression and LDH release (r = 0.84; P < 0.001), and myocardial Plt accumulation (r = 0.85; P < 0.001). We conclude that the deleterious effect of Plt on reperfused myocardium depends on their activation status as represented by P-selectin expression, which is enhanced by ischemia-reperfusion.

Topics: Animals; Blood Platelets; Coronary Disease; Disease Models, Animal; Hemostatics; In Vitro Techniques; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Necrosis; P-Selectin; Platelet Activation; Radionuclide Imaging; Radiopharmaceuticals; Rats; Rats, Sprague-Dawley; Swine; Technetium Tc 99m Exametazime; Thrombin

A left ventricular thrombosis post acute myocardial infarction was detected with Tc-99m HMPAO labeled platelet imaging. The left ventricular thrombosis was already detected on early scans, which allowed for a precise diagnosis during the first 6 hours of the study.

Topics: Aged; Blood Platelets; Heart Diseases; Heart Ventricles; Humans; Male; Myocardial Infarction; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime; Thrombosis

The distribution of 99Tcm-HM-PAO is described in normal man. Since our initial report on the clinical potential of this new radiopharmaceutical in 1984, a number of clinical trials are in progress worldwide. As the tracer has been designed to enable the in vivo assessment of the distribution of cerebral blood flow in man, significant interest in this new 99Tcm-labelled compound can be detected not only in the nuclear medicine practice in general, but in the more specialist areas of medicine such as neurology and psychiatry. In this paper we report findings which should aid in the evaluation of this compound in normal individuals.

Topics: Adult; Aged; Aortic Rupture; Brain; Female; Humans; Male; Middle Aged; Myocardial Infarction; Oximes; Radionuclide Imaging; Reference Values; Technetium; Technetium Tc 99m Exametazime; Tissue Distribution